Heat exchanger and cleaning means therefor



Jan. 3, 1967 B. OSTROFSKY ETAL 3,295,596

HEAT EXCHANGER AND CLEANING MEANS THEREFOR 2 Sheets-Sheet 2 Filed Dec.

INVENTORS. Bernard Osfro fsky Cayce B. Parrish, Jr.

their operation.

United States Patent 3,295,596 HEAT EXCHANGER AND CLEANING MEANS THEREFOR Bernard Ostrofsky, Gary, and Cayce B. Parrish, Jr., Munster, Ind., assignors to Standard Oil Company, Chicago, 11]., a corporation of Indiana Filed Dec. 17, 1963, Ser. No. 331,313 Claims. (Cl. 16584) This invention relates to an apparatus for the removal of deposits from the unexposed tubes of a heat exchanger by sonic waves, which avoids the dismantling of the exchanger and exposing the tubes, and more particularly to a method and apparatus for such removal while the heat' exchanger is on stream and at elevated temperatures. More specifically, the method and apparatus utilize a coupling liquid to avoid temperature effects on the sonic generator;

Deposits are built up on heat exchanger tubes during These deposits restrict flow and seriously decrease the heat transfer efficiencies of the exchangers. Periodic cleaning of the exchangers is required to remove 'these' deposits. Conventionally, these deposits are removed by removing theheat exchanger from operation, removing the tube bundle and cleaning the deposits from the tubes by such techniques as sand blasting. This ap paratus, however, 'is quite expensive both in regard to the cost of removing the exchanger from operation and in removing the tube bundle and subsequent cleaning of the tubes.

Although the dismantling of the heat exchanger is expensive and time consuming, its avoidance would not entirely solve the problems associated with cleaning the heat exchanger tubes. It would still require the removal of the heat exchanger from operation at an elevated temperature to avoid temperature effects on the sonic generator. It is highly desirable to clean the tubes of a heat exchanger without encountering these problems.

One object of this invention is to clean the tubes of a heat exchanger without dismantling the heat exchanger and exposing the tubes. Another object is to clean the tubes of a heat exchanger while the heat exchanger is on stream. Still another object is to clean the tubes of a heat exchanger while the heat exchanger is at an elevated temperature. Other objects of the invention will become apparent in connection with the detailed description of the invention.

Broadly, the invention herein comprises an apparatus for removing deposits from the unexposed tubes of a heat exchanger which is on stream and at an elevated temperature, by transmitting sonic sound waves (including ultrasonic) through a coupling liquid, the shell of the exchanger, and the liquid (between the shell and surrounding the tubes), to produce a deposit removing action in the liquid on the tubes. The coupling liquid provides a means for coupling transducers (preferably ultrasonic generators producing frequencies below about 20,000 c.p.s. and above) to the shell and enclosed liquid and also effectively insulates the transducers from the harmful temperatures of the heat exchanger. The invention also desirably includes a fastening means to fit the combination of the transducers and liquid coupling means tightly to the outer shell surface at pre-determined positions and adapted to permit the convenient rotation of the transducers and liquid coupling means around the shells circumference and/ or along its length to provide the more effective utilization of the transducers.

Having thus indicated the general nature of the invention, reference is made to the accompanying drawings forming a part of this specification and showing one illustrative embodiment of the invention, wherein:

FIGURE 1 is an elevational view of a particular apparatus of the invention.

FIGURE 2 is a plan view showing the mounting plate end of the liquid coupling box which interconnects the transducer to the exchangers shell.

FIGURE 3 is a sectional view taken along lines 33 in FIGURE 2 of the liquid coupling box.

FIGURE 4 is an enlarged side view of a particular apparatus including a sectional segment of a heat exchanger and tube sheet.

In FIGURE 1, the apparatus of the invention numbered 10 is shown positioned ready for generating ultrasonic waves to cause the removal of the deposit by the action of the enclosed liquid on the tubes of heat exchanger 12. Heat exchanger 12 includes shell 13 and illustrative tubes 14, 16, 18, 20, and 22. The apparatus 10 is positioned to transmit the waves through the liquid in the liquid coupling boxes 24 and 26, through shell 13 and the enclosed liquid towards the tubes. It is to be understood that the remaining tubes of the heat exchanger 12 are not shown and that only the other portions of the heat exchanger which are pertinent to the description of the invention are shown in FIGURE 1.

Apparatus 10 includes transducer boxes 28 and 30 fastened to liquid coupling boxes 24 and 26 respectively which are respectively provided with liquid inlet pipes 32 and 34 and outlet'pipes 36 and 38 to provide the supply of the coupling and cooling liquid to coupling boxes 24 and 26. It should be noted that the combination of transducer and liquid coupling boxes 24 and 28, and 26 and 30 are positioned on opposite sides of shell 13 to provide an increase in the removal action of the liquid on the deposits on the tubes. Illustrative of the connection between the mounting plates of boxes 26 and 39 are bolt 49 and nut 42 which connect mounting plates 44 and 46.

Fastening means are provided and connected to each of the liquid coupling boxes and adapted for connecting or fastening the liquid coupling boxes on the outer surface of the shell 13. In FIGURE 1, the fastening means are illustrated by a plurailty of belt means and specifically by cables 48 and 50 which are adapted for fitting the liquid coupling boxes 24 and 26 tightly against the outer surface of shell 13. Cables 48 and 5t) interconnect boxes 24 and 26 by eye bolts 52, 54, 56, and 58. Nut 60 and clamp 62 illustrate the connection of eye bolt 58 on plate 44 and the means for retaining cable 50. Eye bolt 58 annd nut 60 also illustrate adjustable belt means which permit the loosening of boxes 24 and 26 from against shell 13, their rotation around shell 13 and/ or movement along the length of shell 13, and the refastening on the outer surface of shell 13 at new pre-determined positions.

Transducer boxes 28 and 36 contain ultrasonic generators (transducers) which are not shown. These transducers are connected to a power source (also not shown) by cables 64 and 66.

FIGURE 2 is a plan view of mounting plate 44 of liquid coupling box 26. Inlet pipe 34 and outlet pipe 38 are also shown. Openings 68, 70, 72, and 74 are provided for the connection of box 26 to box 24 by means of cables 48 and 50. Eye bolt 56 would pass through opening 68 and eye bolt 58 would pass through opening 72. Illustrative of the connection between 44 and 46 is opening 76 through which bolt 40 passes.

FIGURE 3 illustrates a sectional view of liquid coupling box 26 showing mounting plate 44, bolt 40 and also plates 78 and 80 which fit tightly against shell 13 (not shown). Liquid outlet pipe 38 is also shown.

FIGURE 4 illustrates an enlarged side view of liquid coupling box 26, transducer box 30 and a sectional view of the heat exchanger having shell 13. Fluid inlet pipe 34 is also shown in this figure. The above described apparatus is adpted for cleaning the unexposed tubes 14, 16, 18,

20 and 22 of heat exchanger 12 which is on stream and at elevated temperatures. 13 encompassing a liquid which surrounds the tubes. As noted from the above description, a plurality of transducers are utilized for generating ultrasonic sound waves and are positioned over a plurality of liquid coupling means and in coupling relationship therewith. The liquid The heat exchanger includes shell 7 coupling means is adapted to fit on the outer surface of a water, is introduced through inlet pipes 32 and 34 and Withdrawn through outlet pipes 36 and 38. The flow is regulated to provide adequate coolingof the transducers in boxes 28 and 30.

A power supply is connected to the transducers in boxes 28 and 30 by means of cables 64 and 66. The transducers are preferably magneto-strictive such as those having laminated metal cores with electrical outer windings. A plurality of these transducers are preferably utilized in each transducer box to generate the power at a sufiicient energy level to cause the removal of the tube deposits by the action of the liquid on the tubes. The transducers generate, preferably ultrasonic waves, at frequencies in excess of those which are normally perceivable by the ear. These commonly are in the order of about 20,000 c.p.s. and above, although the usable frequencies include those below 20,000 c.p.s.

The energy from the transducers is transmitted through the liquid in liquid coupling boxes 24 and 26, through shell 13 and the liquid between shell 13 and the tubes. At sufiicient power levels, the liquid acts to remove the deposits from the tubes. This action results from cavitational and other effects of the ultrasonic energyv in the liquid. Although it is not known for certain, some effects may be induced by the ultrasonic energy in the tubes.

It can be seen from the above description that the apparatus of the invention provides a means to carry out the inventive method of cleaning the tubes of a heat exchanger without exposing the tubes and when the heat exchanger.

is on stream and at elevated temperatures. Thus having described the invention, what is claimed is:

1. In combination, with an apparatus for cleaning the 1 unexposed tubes of a heat exchanger which .is onstream,

said heat exchanger having a shell enclosing a liquid which surrounds said tubes, a plurality of transducers for generating sonic sound waves, a plurality ofliquid coupling means, each coupling means being positioned adjacent to and in coupling relationship with each of said transducers and fitted on the outer surface of said heat exchanger shell,

and fastening means connected to each of said liquid coupling means for connecting said liquid coupling means at a pre-determined position on said outer surface of said shell.

2. The apparatus of claim 1 wherein said transducer is a magneto-strictive ultrasonic transducer and said liquid coupling means utilizes water as said liquid.

3. The apparatus of claim 2 wherein said fastening means are a plurality of belt means interconnecting the liquid coupling means and positioning each of said liquid coupling means tightly against the outer surface of said shell.

4. The apparatus of claim 3 wherein said belt means are adjustable to permit the loosening of said liquid coupling means, their rotation around said shell, and their refastening on the outer surface of said shell at a new pre-determined position. t

5. The apparatus of claim 3 wherein said plurality of liquid coupling means is two, and said belt means positions said liquid coupling means on the opposite shellrsurfaces of the heat exchanger.

References Cited by the Examiner UNITED STATES PATENTS 2,514,797 7/1950 Robinson l09 2,855,526 10/1958 Jones' 3lO--8.5

2,864,592 12/1958 Camp 259-4 ROBERT A. OLEARY, Primary Examiner.

CHARLES SUKALO, Examiner. 

1. IN COMBINATION, WITH AN APPARATUS FOR CLEANING THE UNEXPOSED TUBES OF A HEAT EXCHANGER WHICH IS ON STREAM, SAID HEAT EXCHANGER HAVING A SHELL ENCLOSING A LIQUID WHICH SURROUNDS SAID TUBES, A PLURALITY OF TRANSDUCERS FOR GENERATING SONIC SOUND WAVES, A PLURALITY OF LIQUID COUPLING MEANS, EACH COUPLING MEANS BEING POSITIONED ADJACENT TO AND IN COUPLING RELATIONSHIP WITH EACH OF SAID TRANSDUCERS AND FITTED ON THE OUTER SURFACE OF SAID HEAT EXCHANGER SHELL, AND FASTENING MEANS CONNECTED TO EACH OF SAID LIQUID COUPLING MEANS FOR CONNECTING SAID LIQUID COUPLING MEANS AT A PRE-DETERMINED POSITION ON SAID OUTER SURFACE OF SAID SHELL. 